So-called transmitted light illumination is used for illuminating an instrument of a vehicle such as a speed meter and a tachometer. In such transmitted light illumination, illumination light emitted from a light source referred to as a backlight irradiates a dial from a rear surface thereof, and the illumination light is transmitted through only portions corresponding to characters and scales of a speed meter and a tachometer printed on the dial, so as to illuminate the dial.
As a method of achieving the transmitted light illumination, a display in which characters and/or scales in a dial are illuminated, with the transmitted light illumination has been proposed (for example, Patent Document 1). The display is configured to guide light which enters a light guide plate from an incident portion of the light guide plate disposed in the rear surface of the dial to the entire light guide plate through total reflection, and to emit outside a part of the light guided in the light guide plate, so as to illuminate the characters and the scales of the dial.